The research undertaken has been designed to increase our understanding of biological mineralization. New ultrastructural techniques such as frozen thin-sectioning and low-temperature ashing, are applied to bone and shell gland in various stages of the mineralization process. We are determining the location and types of elements found in cells and extracellular matrices. The results should be more representative of in vivo relationships than has been demonstrable in the past because little or no mineral is lost or relocated during tissue preparation. We have selected two different tissues for study in order to provide a comparative basis for the interpretation of results. This should assist in demonstrating the extent to which the findings are part of a general phenomenon. The determination of normal tissue elemental levels and locations provides a basis for recognizing subcellular distributions that accompany or result in disease. The approaches we are employing may provide access for gaining insight into mineral-related pathologies of man.